In general, 5-HT4 receptor agonists are found to be useful for the treatment of a variety of diseases such as gastroesophageal reflux disease, gastrointestinal disease, gastric motility disorder, non-ulcer dyspepsia, functional dyspepsia, irritable bowel syndrome (IBS), constipation, dyspepsia, esophagitis, gastroesophageral disease, nausea, central nervous system disease, Alzheimer's disease, cognitive disorder, emesis, migraine, neurological disease, pain, cardiovascular disorders such as cardiac failure and heart arrhythmia, and apnea syndrome (See TiPs, 1992, 13, 141; Ford A. P. D. W. et al., Med. Res. Rev., 1993, 13, 633; Gullikson G. W. et al., Drug Dev. Res., 1992, 26, 405; Richard M. Eglen et al, TiPS, 1995, 16, 391; Bockaert J. Et al., CNS Drugs, 1, 6; Romanelli M. N. et al., Arzheim Forsch./Drug Res., 1993, 43, 913; Kaumann A. et al., Naunyn-Schmiedeberg's. 1991, 344, 150; and Romanelli M. N. et al., Arzheim Forsch./Drug Res., 1993, 43, 913).
WO2003/57688 discloses 1-alkyl-2-oxo-1,2-dihydropyridine-3-carboxamide derivatives as 5-HT4 receptor modulators. Especially, the compound represented by the following formula is disclosed in Example 4:

However, this compound shows weak affinity to 5-HT4 receptor and low permeability against caco2 membrane.
Therefore, it was desired to find out 5-HT4 receptor agonists which show stronger 5HT4 receptor agonistic activities and better permeability against caco2 membrane in order to reduce side effects.